Lindsey Optics Brilliant Clear Filters are designed to protect expensive cine lenses while maintaining image quality. They will not introduce distortions, color shifts or focus shift. They are made from the finest optical glass and are ground and polished flat to ensure sharp images. The flatness of Lindsey filters is tested on our Zygo phase shift interferometer. Every filter has a 7 layer broadband anti-reflection coating on both sides. Lindsey coatings are extremely durable.